Process for the reduction of grain and its subsequent conversion into bread or like product



P 1938- s. M. SALOMON El AL 2,131,674

PROCESS FOR THE REDUCTION OF GRAIN AND ITS SUBSEQUENT CONVERSION INTOBREAD OR LIKE PRODUCT Filed Jan. 15, 1956 2 Sheets-Sheet 1 9 FEED WHEATWHEAT BRUSH W 3H/Gf/ Wf/[AT D cRum/A/a MILL i JOAN/V6 BOWL com trap;

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PROCESS FOR THE REDUCTION OF GRAIN AND ITS SUBSEQUENT CONVERSION INTOBREAD OR LIKE PRODUCT Filed Jan. 15, 1936 2 Sheets-Sheet 2 TAIL) [Ail475D CtWTRIFl/G/IL DQ555151? CON VE YOR 4 CHI. fiRfA/(ER E/sA mrs. -57?5920/70/1 Patented Sept. 27, 1938 PROCESS FOR THE REDUCTION OF GRAIN ANDITS SUBSEQUENT CONVERSION INTO BREAD OR LIKE PRODUCT Schachna MauriceSalomon and Sune Busch,

London, England, assignors to Sunbred Limited, London, England, a.British company Application January 15, 1936, Serial No.'59,296 In GreatBritain February 11, 1935 4 Claims.

In the process with which the present invention is concerned whendealing with the grain a wholemeal dough is produced containing thewhole of the berry and in such a manner that both the aleurone and germcells are broken down thereby rendering digestive what was previouslynon-digestive. This breaking down of the cells has heretofore beenproposed to be effected by either of two methods one of which may betermed the mechanical method and the other the automatic method.

In the mechanical method the grain after being soaked or steeped inwater is transferred to apressure applying device such as an autoclavewherein the soaking is completed under pressure to produce swelling. Theswelled grain or bran is then milled with the object of breaking downthe cells.

In the automatic method the grain is flrstly ground into meal, thensoaked or steeped in water and then subjected to a continuouslyincreasing pressure to cause penetration of the water through the wallsof the cells. In this automatic method bursting is attempted by suddenlyreleasing the pressure such as by exposing the treated mass to a vacuumwith the object of explosively opening out the cells.

In both of the above methods there is an element of uncertainty. Forinstance in the me- 40 chanical method reliance is placed upon treatmentin an ordinary roller milling machine for bursting the swelled cells.

In the automatic method reliance must be had upon effective penetrationof the walls of the 40 cells by the liquid in which they are soaked as aresult of the externally applied pressure and the 'use of any internalpressure thus produced to effect bursting when the external pressure isreleased.

In a similar process for milling bran it is introduced with water inexcess into a vessel such as an autoclave wherein it is subjected to acontinuously increasing pressure, up to about atmospheres to produceswelling of the albumen. After this treatment the bran is mechanicallymilled in an attempt to effect bursting the cells.

From experiments carried out with the above processes we have found thatbursting or breaking down of the cells takes place only to'a very 5limited extent.

The principal object of the present invention is to provide a processfor treating whole grain or bran which will be commercially practicableand which will result in the breaking down or bursting of the greaterproportion of the aleurone and germ cells. 1

A further object of the invention is to provide a process which can becarried out as a continuous process and in which pressure applyingdevices such as autoclave may, if desired, be dispensed with.

Our experiments have shown us that it is unnecessary to bring thealeurone cells into va swollen condition before they can be burst orbroken down. By subjecting the grain or bran to a crushing process torender the same sufliciently liquid absorbing we have found that simplysoaking the same in water will soften the walls of the cellssufliciently as to render the same amenable to bursting by compression.Simple compression alone however such as by passing soaked butnon-swelled material through pressure rolls does not act with theefliciency and rapidity required in a commercial process. We have foundhowever, that if crushedand soaked material is subjected to combinedcompression and attrition whilst in a sufliciently attenuated conditionthat 90% and over of the cells will be broken down and that such processcan be carried out continuously and expeditiously. To effect bursting bycompression alone it is advisable flrstly to swell the crushed product.

Broadly the present invention consists of a process for the reduction ofwhole grain or bran which comprises crushing the grain or bran to renderthe same sufliciently liquid absorbing, soaking the crushed product,preferably at atmospheric pressure, to soften the cells, and thenbreaking down the cells by subjecting the soaked product to compression,preferably combined 45 .of a conventional dough mixer, the soakingperiod being from two to three hours according to the nature of thegrain or bran. We have also found that the combined compression andattrition may be applied to the dough in a most expeditious andsatisfactory manner by means of a machine comprising a plurality ofmetal rolls of comparatively large diameter having highly polishedperipheries said rolls being rotated at relatively different speeds andforcible towards each other by pressure applying means.

In use in the present process the rollers are set with their peripheriesabout .0020" apart to permit of the entrainment of a film of dough.Pressure is then applied to the rotating rollers until the issuing doughis in the form of a very thin unbroken film. The pressure needed forthis purpose is considerable and the resulting compression of the doughcombined with the attrition produced by the differing speeds of therollers has been found to be sufllcient eflectively to break down boththe aleurone and germ cells of the grain.

The resulting product in the case of whole grain after being conditionedby the addition of yeast salt etcetera in a dough mixer is convertedinto wholemeal bread or like product by the ordinary baking processes.

Where bran alone has been treated by this process the same may beconverted into bread by adding to it a suitable percentage of ordinaryflour the whole being then mixed together with yeast salt etcetera in adough mixer after which it is converted into bread by the ordinarybaking processes.

The term soaking when employed in the general sense is intended to coverboth simple soaking at atmospheric pressure or pressure soaking such asin an autoclave to effect a swelling of the crushed products. Swellingwill of course occur also to a limited extentby osmotic penetration bythe non-pressure method it depending of course upon the period theproduct is allowed to soak.

In order that the invention may be clearly understood and carried intoeffect a plant for treating whole meal such as wheat and a plant fortreating bran alone will now be described by aid of the diagrammaticaccompanying drawings in which:- i

Fig. 1 is a. flow sheet illustrating the plant for treating the wholewheat and Fig. 2 is a. flow sheet illustrating the plant for treatingbran alone.

Referring to the plant illustrated in Fig. 1, the wheat in the form ofthe whole berry after having been preliminarily cleaned by conventiohalmethods is fed to a warehouse separator A wherein further cleaning takesplace. The berries then pass in succession through a wheat scourer B andwheat brush C respectively. The

berries thus cleaned and retaining the husk or bran, are then passedthrough a three high wheat crushing mill D which reduces the whole berryto a granular form of such fineness as to render the same readily liquidabsorbing. The crushed product from the mill is then deposited in asoaking bowl E containing water wherein it remains as a mass for asoaking period of anything from two to three hours according to thenature of the grain. After this period the cell walls have becomesufficiently; softened for the breaking down process to be effected. Thesoaked mass is then conveyed to a cell breaker F wherein it is subjectedto combined compression and attrition whilst in the form of a thin film.

The cell breaker in the plant illustrated is a machine which broadlycomprises a plurality of smooth surfaced contacting rollers which arerotated at differing speeds with their peripheries in hard contact witheach other. As previously explained the rollersare set with theirperipheries about two thousandths of an inch apart to permit of theentrainment of a film of dough. The rollers are then forced hardtogether whilst they are rotating with the result that the dough issubjected to very drastic compression and attrition and issues at thedelivery end in the form of a very thin unbroken film from. which mostof the water has been extruded and in which nearly all the bran andother cells as well as the germ have been broken down. This latter facthas been clearly demonstrated by microscopic examination of theresulting product. From the cell breaker the reduced product consistingof the whole wheat berry including the bran is then taken to a doughmixer not shown wherein it is conditioned by the addition of yeast,salt, etcetera. It then goes through the normal baking processes forconversion into whole meal broad or like product.

In the plant for treating bran alone the material after having passedthrough the usual cleaning processes, is fed through one pair of rollsof a four roller mill G. The partially reduced product is then deliveredto a sieve H which separates out the tailings which are elevated to thefour roller mill G for passage between the second pair of, rolls of thesame, and re-entry into the sieve. From the sieve the bran passesthrough a single roller mill I and thence to a centrifugal dresser J.This process is repeated in a further roller mill K and centrifugaldresser L. From each dresser a return is provided for effecting are-entry of the coarser particles to the feeds to the respective rollermills. By this means the bran particles are reduced to approximately thesame size.

3 The crushed bran is then fed into a liquid mixer M, to ensure that theparticles shall each take up a certain amount of water. The sodden' massis then transferred to a soaking bowl N wherein it is left for from twoto three hours to soften the cells. The soaked bran is then conveyed tothe cell breaker'O which is the same as used in the wheat plantillustrated in Fig. 1. The treatment to which the soaked bran issubjected in the cell breaker is the same as in the case of the wholewheat. The bran thus treated by this process may be converted into breadby adding to it a suitable percentage of ordinary flour, the whole beingthen mixed together with yeast, salt, etcetera in a dough mixer afterwhich it passes through the ordinary baking processes. Although simplesoaking in an open soaking bowl has been found sufficient to eflect therequired softening of the cells and germ, the crushed grain or bran maybe caused to swell by introducing the same into an autoclave containingliquid and therein subjecting the same to the pressure required for thepurpose. As however the operation of the autoclave adds somewhat to thecost of the process and as its use is unnecessary it is preferred todispense with it.

Similarly whilst compression alone has been found sufllcient to breakdownthe cells its action is so uncertain and slow as compared withbreaking down by subjection to combined compression and attrition thatthe latter method is preferred. It must be understood however that theuse of the autoclave and/or compression in a process according to thisinvention is not disclaimed but comes within the broad definition of theinvention set forth in the opening statements of the specification andin some of the appended claims.

It is also to be understood that the soaking bowl used in both plantsmay form part of a conventional dough mixing machine in which case theseparate liquid mixer M may be dispensed with, mixing and soaking beingefiected in a single machine.

Having now particularly described and ascertained the nature of our saidinvention and in what manner the same is to be performed, we declarethat what we claim is:--

1. Process for the production of a cereal substance including aleuronecells which comprises the steps of firstly partially milling the cerealsubstance to reduce the same to a product of substantially powdered formcapable of absorbing liquid upon simple soaking which contains the cellsin a substantially unreduced form soaking the partially milled productfor a period of time sufilcient to soften and swell said cells andfinally subjecting the soaked and softened product to combinedcompression and attrition by causing the same to pass between pairs ofsmooth rollers rotating at differing speeds said rollers being forcedtogether with a pressure sufilcient to squeeze and rub saidproduct intoa thin film and to break down the walls of the softened cells by theaction of the pressure applied during such squeezing and rubbing.

2. Process for the production of bread from whole grain including thebran comprising the steps of firstly partially milling the whole grainberries with their bran coverings to reduce the whole to a flour formwhich contains the aleurone and germ cells in a substantially unreducedform, soaking the partially milled product for a period of timesufiicient to soften and swell said cells, subjecting the soaked andsoftened product to combined compression and attrition by causing thesame to pass between pairs of smooth rollers rotating at differingspeeds said rollers being forced together with a pressure sufiicient tosqueeze and rub said product into a thin film and to break down thewalls of the softened cells by the action of the pressure applied duringrubbing and squeezing and finally subjecting the dough like productafter being conditioned by the addition 01' yeast, salt, etcetera. tothe ordinary bread baking processes.

3. Process for the production of bread from bran which comprises thesteps firstly of partially milling the bran to reduce the same to aproduct of substantially powdered form capable of absorbing liquid uponsimple soaking and being forced together with a pressure sufficient tosqueeze said product into a thin film and to break down the walls of thesoftened cells by the direct action of the rubbing and squeezing towhich they are thereby subjected, adding to the dough-like product asuitable percentage of flour obtained from the berry of the grain,simultaneously mixing and conditioning the same and finally subjectingthe mixed and conditioned product to the ordinary bread bakingprocesses.

4. Process for the production of bread from bran which comprises thesteps of firstly partially milling the bran to reduce the same to aproduct of substantially powdered form capable of absorbing liquid uponsimple soaking and which contains the cells in a substantially unreducedform, soaking the partially milled product for a period oi. timesufiicient to soften and swell the contained cells, subjecting thesoaked and softened product to combined compression and attrition bycausing the same to pass between pairs of smooth rollers rotating atdifierent speeds said rollers being forced together with a pressuresuflicient to squeeze and rub said product into a thin film and to breakdown the walls of the softened cells by the direct action of the rubbingand squeezing to which they are thereby subjected, adding to thedough-like product a suitable percentage of fiour which contains cellsin a broken down condition and which is obtained by similarly treatingthe berry of the grain, simultaneously mixing and conditioning thedough-like product and the added flour and finally subjecting the mixedand conditioned product to the ordinary bread baking processes.

SCHACHNA MAURICE SALOMON. SUNE BUSCH.

